The access authentication promotes information sharing among authorized users and prohibits others from accessing the information. Particularly, in a session for a user to a use a local network via WIFI, the entry of a security key by the user is not always an easy and user-friendly way; furthermore, the security key left in the computer after the session may allow the user without authorization to access other sessions. There exist some solutions. In a first solution, a flash drive may be distributed to authorized users; the flash drive is with preconfigured network settings or a text file containing a password. With the first solution, a computer or other electronic device must have a USB drive, and flash drive data can be easily copied. In a second solution, two-dimensional barcode may be used for a user to scan for the purpose of authentication. With the second solution, a computer or other electronic device must have a camera; in addition, a picture of the two-dimensional barcode can be easily taken and distributed without authorization. In a third solution, near field communication (NFC) may be used for a user to be authenticated by bringing a computer to proximity of a router; wherein both the computer and the router must be NFC enabled. With the third solution, the user must bring the computer close enough to the router. Under the situation of multiple users, the third solution is unsuitable and inconvenient.